1. Field of the Invention
This invention relates to multilobal fibers having a variety of uses. More particularly, this invention relates to such fibers having at least about three lobes which are useful in such diverse applications as filtering, wicking, insulating and other applications.
2. Prior Art
Nylons such as nylon 6, nylon 66, nylon 4, nylon 610 and nylon 11 are known for use in the manufacture of fibers. Illustrative of these fibers are those described in J. Gordon Cook, "Handbook of Textile Fibers" 5th Ed. Trowbridge Great Britain (1984) pp. 19-20, 308.
Polyesters are also well known materials for the manufacture of fibers. Illustrative of such fibers are those described in U.S. Pat. Nos. 4,454,196; 4,410,473; and 4,359,557.
Other well known polymeric materials for use in the manufacture of fibers are polyolefins. Illustrative of such fibers are those described in U.S. Pat. Nos. 4,137,391; 4,587,154; 4,567,092; 4,562,869; and 4,559,862.
Fibers containing mixtures of polyolefins and polyesters are known. For example, U.S. Pat. No. 3,639,505 describes fibers and films composed of a polymer alloy comprising an intimate blend of polyolefin, a minor amount of polyethylene terephthalate and 0.2 to 5 parts per hundred parts of polymer of a toluene sulfonamide compound which are described as having improved receptivity to dispersed dyes.
Bicomponent textile filaments of polyester and nylon are known in the art, and are described in U.S. Pat. No. 3,489,641. According to the aforesaid patent, a yarn that crimps but does not split on heating is obtained by using a particular polyester.
It is also known to employ as the polyester component of the bicomponent filament a polyester which is free from antimony. The antimony in the polyester reacts with nylon to form a deposit in the spinnerette which produces a shorter junction line, and thus a weaker junction line. Such products are claimed in U.S. patent application Ser. No. 168,152, filed July 14, 1980.
It is also known to make bicomponent filaments using poly[ethylene terephthalate/5-(sodium sulfo) isophthalate]copolyester as the polyester component. U.S. Pat. No. 4,118,534 teaches such bicomponents.
It is also known to make bicomponent filaments in which one component partially encapsulates the other component. U.S. Pat. No. 3,607,611 teaches such a bicomponent filament.
It is also known to produce bicomponent filaments in which the interfacial junction between the two polymeric components is at least in part jagged. U.S. Pat. No. 3,781,399 teaches such a bicomponent filament. Bicomponent filaments having a cross sectional dumbbell shape are known in the art. U.S. Pat. No. 3,092,892 teaches such bicomponent filaments. Other nylon/polyester bicomponent fibers having a dumbell cross sectional shape having a jagged interfacial surface, the polyester being an antimony-free copolyester having 5-(sodium sulfo) isophthalate units are known. U.S. Pat. No. 4,439,487 teaches such fibers. The surface of such bicomponent filament is at least 75% of one of the polymeric components. Still other nylon/polyester bicomponent sheath/core fibers are described in Japan Patent Nos. 49020424, 48048721, 70036337 and 68022350; and U.S. Pat. Nos. 4,610,925; 4,457,974 and 4,410,928.
Fibers have previously been prepared from blends of polyamides with minor amounts of polyesters such as poly(ethylene terephthalate). Intimate mixing before and during the spinning process has been recognized as necessary to achieve good properties in such blended fibers. It is furthermore known that the fine dispersions in fibers of polymer blends are achieved when both phases have common characteristics such as melt viscosity. See D. R. Paul, "Fibers From Polymer Blends" in Polymer Blends, vol. 2, pp. 167-217 at 184 (D. R. Paul & S. Newman, Academic Press 1978).
Graft and block copolymers of nylon 6/nylon 66, nylon 6/poly(thylene terephthalates) and nylon 6/poly(butylene terephthalate) have been formed into grafts which can be spun into fibers. For example, U.S. Pat. No. 4,417,031, and A. Aharoni, Polymer Bulletin, vol. 10, pp. 210-214 (1983) disclose a process for preparing block and/or graft copolymers by forming an intimate mixture of two or more polymers at least one of which includes one or more amino functions, as for example a nylon, and at least one of the remaining polymers includes one or more carboxylic acid functions, as for example a polyester, and a phosphite compound; and thereafter heating the intimate mixture to form the desired block and/or graft copolymers. U.S. Pat. No. 4,417,031 disclose that such copolymers can be spun into fibers.
Multilobal fibers are known. For example, U.S. Pat. Nos. 4,648,830 and 4,770,938 describe hollow trilobal fibers composed of nylons such as nylon 6 and nylon 66. These fibers are disclosed as having improved bulk, soil hiding and resiliency when tuffed into a fiber.
Similarly, U.S. Pat. No. 3,493,450 is directed to trilobal filaments with axial holes in the lobes and the center of the cross-section of the filaments. Such filaments are spun from conventional synthetic polymers such as nylon 6, nylon 66, nylon 4, nylon 610, polyethylene, polypropylene, and polythylene terephthalate
U.S. Pat. No. 3,493,459 describes a complex multilobal textile filament having a multitude of holes and lobes and composed of polymers such as nylon 66, nylon 6/bb, nylon 6/610/66, nylon 610, nylon 4, nylon 6, nylon 11, polyethylene terephthalate, polypropylene, and polyethylene. These filaments are disclosed as providing increased cover and exhibiting reduced prismatic luster. European Patent No. 0 189 401 and U.S. Pat. No. 4,713,289 disclose polyester fibers of cruciform cross-section which are disclosed as exhibiting water dispersibility, better uniformity, more opacity, good permeability and an attractive flannel-like hand to the resulting wet-laid fabrics. U.S. Pat. No. 4,279,053 discloses tri or tetra-locular oriented polymeric paint brush bristles which are composed of thermoplastic polymeric materials such as polyamides, polyesters and polyolefins, and which are disclosed as exhibiting excellent uniformity of cross-sectional configuration, amenability to flagging, resistance to curl and overall high performance as a brush bristle.